1. Field of the Invention
The present invention relates to a method of reading a bar code formed on an object subjected to detection of information, such as a photographic film.
2. Description of the Prior Art
Provision of a bar-code area on a portion of a photographic film makes it possible to record information, such as exposure correction data, which is used when the film is printed.
It is, however, not easy to read the bar code since it is generally formed in a narrow area between one side edge of the film and one of the sprocket-engaging perforations which are formed on both sides of the series of images on the film.
More specifically, the bar code formed on the photographic film consists of two rows of bars respectively serving as a clock track and a data track. The width of each track is about 1 mm, and the minimum distance between adjacent bars is about 0.45 mm in the film advancing direction.
Such an arrangement of the bar code involves the possibility of a read error. More specifically, when the film is intermittently fed, mechanical vibrations may be undesirably generated at the time of starting and stopping the operation of advancing the film, and this fact can easily lead to erroneous double reading of the same data.
Further, various films generally differ from each other in the density of light and dark portions of the bar code, and there are large variations in the density.
The density variations may cause a type of read error that will cause a light portion of the bar code to be erroneously read as a dark portion or vice versa.